A study says that up to 50% of the beaches in Brazil, Uruguay and Argentina are at risk of extinction by 2100.

• Rio room Approves a project to expand restrictions on buildings that shade the sand and beach boardwalk

The phenomenon known as coastal pressure, which reduces the distance between the sea and urban infrastructure, was one of the main topics of the meeting. Rising sea levels, due to climate change, are exacerbating the situation, making coastal cities more vulnerable to attacks from the ocean.

Omar DeFeo, a professor at the University of the Republic (UdelaR) in Uruguay, highlighted the seriousness of the problem during the event: “Almost half of the beaches will disappear by the end of the century. Uruguay, Brazil and Argentina share these resources. Therefore, we must work together with Brazilian scientists to manage and conserve coastal ecosystems.”

Recent research reinforces this warning. A study conducted by Guilherme Corte, in collaboration with Defeo and funded by FAPESP, analyzed 90 points on 30 beaches in northern São Paulo, including Ubatuba, Caraguatatuba, Ilhabela and São Sebastião. The results, published in the journal Marine Pollution Bulletin, 2023, showed that the number of visitors is the urban variable that most reduces species richness and biomass, especially in submerged areas close to rocky beaches and artificial reefs.

Furthermore, human activities such as building kiosks, walkways and parking lots on the sand, as well as mechanical cleaning, have had ongoing negative impacts. In Ilhabela, for example, the presence of large numbers of tourists during the high season has reduced the diversity of polychaete fauna and molluscs. In Caraguatatuba, near-shore construction significantly affected biomass in flooded areas, while Ubatuba recorded an increase in opportunistic species, such as polychaetes that benefit from organic matter generated by visitors.

The study also confirms that urbanization does not only affect dry sands: both construction and the arrival of large numbers of tourists harm submerged areas, exacerbating species loss and changing the balance of the coastal ecosystem.

Globally, another study by DeFeo, in partnership with Brazilian scientists, analyzed 315 beaches and concluded that one in five suffered from severe or severe erosion. Human impact, especially on reflective and intermediate beaches, has been identified as one of the main drivers of degradation, along with sea level rise and wind and wave action.

The coastal ecosystem depends on the balance between three interconnected zones – the dune, the beach and the surf zone – and the constant exchange of sediments. “If urbanization removes sand dunes, the result could be the destruction of coastal homes,” warns DeFeo, remembering that changes in any of these areas affect the entire system.